Healthy: subjecting myself to shower or full body immersion in very cold water, porn, binge watching a series until I fall asleep to it, several mile long walks, telling someone supportive.
Effective but definitely not healthy: food binge, self injury. These things get you high by causing physical pain. Drugs can work in the moment but weed can be terrifying if you're not a habitual user, using harder drugs you can easily end up more suicidal when you crash, and just stay far away from psychedelics in this state.
Hopefully I don't get jumped on for suggesting this but if you have the means readily available and want to short circuit the impulse but just can't do it yourself the hospital is an option. I did this once. It was super unpleasant but if you know you're just feeling impulsive and you need someone to help you stop, the psych ward's main focus is to stabilize people in crisis. Just make sure you know what you're getting into in terms of your rights.
When I went I hadn't been able to eat or sleep much to speak of for a few days and knew I wasn't being rational. It was New Year's Eve and I was running frantically from store to store trying to buy a camp stove so I could carbon monoxide myself to death, all based on a coin toss, trying not to freak out on the store employees as they did their best to find a location that had what I was looking for.
At the hospital they gave me melatonin and because that got me to sleep they didn't force me to take any other meds. It helped that I went voluntarily. They thought I was manic but I was firm in explaining that I had a raging case of PMS that happened to coincide with some crazy work stuff, hence the effectiveness of melatonin in breaking my multi day insomnia.
Like I said, though, it was really unpleasant in there. They strip search you, transport you by gurney, watch you 24/7, the bathroom doors don't lock, and you don't have anywhere private or quiet. Even away from the TV that will never turn off, people on antipsychotics can end up in a never ending back and forth shuffle that you can't get away from. But if you have the means readily available, you want to stop the impulse and truly don't think you can, this is an option.